Back to Search
Start Over
Subsoil biogeochemical properties induce shifts in carbon allocation pattern and soil C dynamics in wheat.
- Source :
- Plant & Soil; Sep2019, Vol. 442 Issue 1/2, p369-383, 15p, 1 Diagram, 1 Chart, 7 Graphs
- Publication Year :
- 2019
-
Abstract
- Aims: Microbial turnover processes are typically restricted by low substrate availability in the subsoil. We hypothesized that SOM decomposition increases with plant density and decreases with N fertilization: We expected a greater rate of C allocation to the rhizosphere in the topsoil than in the subsoil treatments. Methods: In order to simulate different degrees of rhizodeposition, wheat was planted in pots at four different densities. The plants were continuously labeled with <superscript>13</superscript>C-depleted CO<subscript>2</subscript>. Soil CO<subscript>2</subscript> efflux was partitioned for root- and SOM-derived CO<subscript>2</subscript>. Moreover, we determined the enzyme kinetics by measuring catalytic efficiency and enzyme stoichiometry in both topsoil and subsoil. Results: Shoot biomass and the shoot to root ratio were significantly higher for plants grown in the topsoil compared with the subsoil, which demonstrated higher relative C allocation to root biomass in the subsoil treatment. Despite the similar size of the rhizosphere, root-derived CO<subscript>2</subscript> was always higher in the topsoil compared with the subsoil treatment, indicating enhanced root exudation. Effect sizes of all enzyme activities showed stronger magnitudes for the subsoil treatments. This was in line with a two-times increase of the effect size of SOM decomposition in the subsoil relative to topsoil. Conclusions: Overall, the plants in the subsoil treatments allocated more C to root biomass, less C to shoot biomass, and substantially less C to root exudates. However, the effect sizes of both SOM decomposition and enzyme activities were higher in the subsoil than in the topsoil, reflecting a stronger sensitivity to C inputs. [ABSTRACT FROM AUTHOR]
- Subjects :
- SOIL dynamics
SUBSOILS
ENZYME kinetics
WHEAT
PLANT spacing
TOPSOIL
Subjects
Details
- Language :
- English
- ISSN :
- 0032079X
- Volume :
- 442
- Issue :
- 1/2
- Database :
- Complementary Index
- Journal :
- Plant & Soil
- Publication Type :
- Academic Journal
- Accession number :
- 138431337
- Full Text :
- https://doi.org/10.1007/s11104-019-04204-9